COVID-19 vaccine makers such as Pfizer should focus on getting shots to poor countries instead of trying to persuade wealthy nations to give their citizens booster shots, World Health Organization (WHO) officials said at a press briefing held Monday.

Despite a lack of evidence that third doses of vaccines are necessary, drug companies are lobbying the United States and other Western countries to buy and distribute third doses as boosters, the Associated Press reported.

On Monday, representatives from Pfizer lobbied officials at the U.S. Food and Drug Administration on the need for booster shots of its two-dose vaccine, even though many experts are skeptical most people will ever need one.

In the meantime, only 1% of people in poor countries have received even one COVID-19 vaccine dose, according to Tom Hart, acting CEO of the advocacy group ONE Campaign.

"The idea that a healthy, vaccinated person can get a booster shot before a nurse or grandmother in South Africa can get a single jab is outrageous," he told the AP.

WHO director-general Tedros Adhanom Ghebreyesus said that global disparities in vaccine supply are largely being driven by greed.

"We are making conscious choices right now not to protect those in need," and the immediate priority must be to vaccinate people who have yet to receive a single dose, Tedros said.

He urged Pfizer and Moderna to "go all out to supply COVAX, the Africa Vaccine Acquisition Task Team and low- and middle-income countries with very little coverage." COVAX is an initiative to distribute vaccines globally.

Dr. Michael Ryan is emergencies chief at WHO. At the briefing, he said that if rich countries decide to give booster shots to their people rather than donating them to the developing world, "we will look back in anger and I think we will look back in shame."

Dr. Soumya Swaminathan, WHO's chief scientist, added that, "at this point ... there is no scientific evidence to suggest that boosters are definitely needed." She said that if boosters do someday prove necessary, the decision to approve them "has to be based on the science and data, not on individual companies declaring that the vaccines should now be administered as a booster dose."

Pfizer and another leading vaccine maker, Moderna, have each agreed to supply small amounts of COVID-19 vaccine to developing nations through COVAX, but most of their shots have been reserved by rich countries, the AP said.

In the meantime, COVAX's efforts have stalled in recent weeks, with 60 developing nations having to halt immunization efforts as supplies were cut off from a major supplier until at least the end of the year.

SARS-CoV-2 isn't waiting, however: Tedros said that after a 10-week drop in global coronavirus deaths, death rates are climbing again and the highly infectious Delta variant is "driving catastrophic waves of cases."